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Joel Ullom (Fed)

Dr. Joel Ullom leads the NIST Quantum Sensors Division. He is also a Lecturer in the Department of Physics at the University of Colorado Boulder. Dr. Ullom has worked in the fields of low temperature sensors, quantum electronics, and cryogenic systems since 1994. During this time, he has done research to understand and improve the performance of superconducting transition-edge sensors. He has also worked to develop different types of refrigerators including microcoolers based on quantum tunneling and macrocoolers that reduce the need for liquid cryogens. Dr. Ullom has developed and disseminated a variety of instruments based on multiplexed arrays of cryogenic sensors.

Research Interests

  • cryogenic sensors
  • multiplexed readout techniques
  • advanced cryogenics
  • radiation detection
  • applications of cryogenic sensors in materials analysis, astrophysics, cosmology, fundamental parameters, and quantum information science

Awards

Publications

A tabletop x-ray tomography instrument for nanometer-scale imaging: demonstration of the 1,000-element transition-edge sensor subarray

Author(s)
Paul Szypryt, Nathan J. Nakamura, Dan Becker, Douglas Bennett, Amber L. Dagel, W.Bertrand (Randy) Doriese, Joseph Fowler, Johnathon Gard, J. Zachariah Harris, Gene C. Hilton, Jozsef Imrek, Edward S. Jimenez, Kurt W. Larson, Zachary H. Levine, John Mates, Daniel McArthur, Luis Miaja Avila, Kelsey Morgan, Galen O'Neil, Nathan Ortiz, Christine G. Pappas, Dan Schmidt, Kyle R. Thompson, Joel Ullom, Leila R. Vale, Michael Vissers, Christopher Walker, Joel Weber, Abigail Wessels, Jason W. Wheeler, Daniel Swetz
We report on the 1,000-element transition-edge sensor (TES) x-ray spectrometer implementation of the TOMographic Circuit Analysis Tool (TOMCAT). TOMCAT combines

Proof-of-Principle Experiment for Testing Strong-Field Quantum Electrodynamics with Exotic Atoms: High Precision X-Ray Spectroscopy of Muonic Neon

Author(s)
Douglas Bennett, W.Bertrand (Randy) Doriese, Malcolm Durkin, Joseph Fowler, Johnathon Gard, Gene C. Hilton, Kelsey Morgan, Galen O'Neil, Carl D. Reintsema, Dan Schmidt, Daniel Swetz, Joel Ullom, Takuma Okumura
To test the bound-state quantum electrodynamics (BSQED), we have performed high precision x- ray spectroscopy of the 5g→4f and 5f→4d transitions (BSQED

Patents (2018-Present)

Compact Low-power Cryo-Cooling Systems For Superconducting Elements

NIST Inventors
Joel Ullom and Vincent Kotsubo
A compact, low power cryo-cooler for cryogenic systems capable of cooling gas to at least as low as 2.5 K. The cryo-cooler has a room temperature compressor followed by filtration. Within the cryostat, four counterflow heat exchangers precool the incoming high-pressure gas using the outflowing low
X-Ray Spectrometer

X-Ray Spectrometer

NIST Inventors
Kevin L. Silverman , Carl D. Reintsema , Galen O'Neil , Luis Miaja Avila , Daniel Swetz , W.Bertrand (Randy) Doriese , Dan Schmidt , Bradley Alpert , Joseph Fowler , Joel Ullom , Ralph Jimenez and Gene C. Hilton
This invention includes: an x-ray plasma source that produces primary x-rays; an x-ray optic that transmits and focuses the primary x-ray onto a sample jet from which fluorescence x-ray are emitted; and a microcalorimeter array detector that measures the energy of the incoming fluorescence x-rays
Created October 9, 2019, Updated October 23, 2023